Sciatica

Definition

Sciatica describes pain or discomfort in the distribution of the sciatic nerve or its components. This nerve runs from the lower part of the spinal cord, down the back of the leg, to the foot. Injury to, or pressure on, the sciatic nerve can cause the characteristic pain of sciatica—a sharp or burning pain that radiates from the lower back or hip, following the path of the sciatic nerve to the foot.

Description

The sciatic nerve is the largest and longest nerve in the body. It supplies sensation from the lower back to the foot. The nerve originates in the lumbar region of the spinal cord. As it branches off from the spinal cord, it passes between the bony vertebrae (the component bones of the spine) and runs through the pelvic girdle (hipbones). The nerve passes near the hip joint and continues down the back of the leg to the foot.

Sciatica is a fairly common disorder. Approximately 40% of the population suffers from it at some point in their lives; however, only about 1% experience any sensory or motor deficits. Sciatic pain has several root causes, and its treatment is directed to the underlying problem.

Of the identifiable causes of sciatic pain, lumbosacral (LS) radiculopathy and back strain are the most frequently suspected. The LS area is the lower part of the spine, and radiculopathy describes pain radiating from pressure on a spinal nerve roots. This area between the vertebrae (hard bones) is cushioned with a disk of shock-absorbing tissue. The spinal canal, comprising the spinal cord and other nerve roots, is hollow and lies in the middle of the spinal column. It is the disks between the vertebrae that enable the back to bend or flex.

A "ring" of cartilage, gristle-like in character, is found the outer edge of the disk (the annulus). The disk's center (nucleus) is a substance like gel. When a disk ruptures, or herniates, it does so because of wear-and-tear, excessive weight, poor posture, injury (perhaps due to improper lifting), or disease. The center nucleus pushes the outer edge of the disk into the spinal canal, putting pressure on the nerves. The spinal nerve root may become compressed by the shifted tissue or the vertebrae. This compression of the nerve root sends a pain signal to the brain. Although the injury is actually suffered by the nerve roots, the pain may be perceived as originating anywhere along the sciatic nerve. Further, if fragments of the disk lodge in the spinal canal, the nerves that control bowel and urinary functions may be damaged. Incontinence may result.

Sciatica is largely a symptom of a herniated disk. However, compression of the sciatic nerve can also present as muscle spasms in the lower back (back strain). In this case, pressure is placed on the sciatic nerve. In rare cases, infection, cancer, bone inflammation, or other diseases may cause pressure. Another possible cause of sciatica is piriformis syndrome.

As the sciatic nerve passes behind the hip joint, it shares the space with several muscles. One of these muscles, the piriformis muscle, is closely associated with the sciatic nerve. In some people, the nerve actually runs through the muscle. If this muscle is injured or has a spasm, it places pressure on the sciatic nerve, in effect, compressing it.

In many sciatica cases, the specific cause is never identified. About half of affected individuals recover from an episode within a month. Some cases persist and may require aggressive treatment. In other cases, the pain returns or becomes chronic.

Causes and symptoms

Patients with sciatica may experience low back pain, but the most common symptom is pain that radiates through one buttock and down the back of the leg. The most frequently identified cause of pain is compression or pressure on the sciatic nerve. The extent of the pain varies. Some patients describe pain that centers in the area of the hip; others feel discomfort all the way to the foot. The quality of the pain also varies; it may be described as tingling, burning, prickly, aching, or stabbing.

Onset of sciatica may be sudden, but it might also develop gradually. The pain may be intermittent or continuous. Certain activities (such as bending, coughing, sneezing, or sitting) can worsen the pain.

Sudden loss of bowel or bladder control, weakness in the legs, buttocks, or torso, as well as numbness that goes upwards from the toes or the feet, may indicate a sciatic condition.

Chronic pain may arise from more than simple compression of the nerve root. Discogenic pain, the result of injury to the innervated portions of the annulus fibrosus, is a common cause of sciatica. Pain is generally felt in the buttocks and in the posterior thigh.

According to some pain researchers, physical damage to a nerve is only half of the equation. A theory developed in 2001 proposes that some nerve injuries result when certain neurotransmitters and immune system chemicals that exacerbate and sustain a pain message. Even after the injury has healed or the damage has been repaired, the pain lingers. Effective management of this type of pain is difficult. Another theory that has been put forward is that back problems may be inherited. This theory presupposes that a genetic abnormality is responsible for a number of cases of spinal disk disease cases. This defect makes people susceptible to rupture when the back is strained. The investigators claimed that 25% of all cases of sciatica, lower back problems, and discomfort higher in the spine, might be attributable to this gene defect. When classic symptoms are absent, identification of the defect could enable diagnosis of disease, thereby facilitating the therapeutic process.

Diagnosis

Establishing the diagnosis requires taking a thorough medical history and performing a focused physical examination. The patient is asked about the location, nature, and duration of the pain, and the details of any accidents, injuries or unusual activities that may have occurred prior to the onset of sciatica. This information provides clues that may point to back strain or injury to a specific location.

Back pain from disk disease, piriformis syndrome, and back strain must be differentiated from more serious conditions, such as cancer or infection. In spring 2001, Dr. T. S. J. Elliott, professor of microbiology at University Hospital in Birmingham, England, conducted a new study—the results of which were published in The Lancet. The doctor found hidden infections in 43 of 140 sciatica (30.7%) patients who suffered from persistent pain originating in the sciatic nerve. (The sciatic nerve of the leg is the largest nerve in the body.) Dr. Elliott believes that when the spine suffers a minor trauma, an organism enters the body. This organism causes sciatica that is continuous, with the resulting inflammation being caused by the infection. Further, he postulated that if imaging studies do not show injury, then there may be something to the physician's study.

More investigations need to be done, however, evaluating the success of antibiotics (used to fight infections) in treating sciatica. Lumbar spine stenosis, an overgrowth of the covering layers of the vertebrae that narrows the spinal canal, must also be considered.

A straight leg-raising test is often performed. The patient lies supine, and the health care provider raises the affected leg to various heights. This test pinpoints the location of the pain and may reveal whether it is caused by a disk problem. Other tests, such as observing the patient rotate the hip joint, may provide information about involvement of the piriformis muscle if the patient experience pain. Piriformis weakness is tested with additional leg-strength maneuvers.

Further tests may be conducted depending on the patient's history, results of the physical examination, and response to initial treatment. Diagnostic tests may include traditional x rays, magnetic resonance imaging (MRI), and computed tomography scans (CT scans ). Other tests include electromyography (studies of the electrical activity generated as muscles contract), nerve conduction velocity testing, and evoked potential testing. Myelography, a more invasive test, involves injecting a contrast medium into the spinal subarachnoid space between the vertebrae and taking x-ray images of the spinal cord. Myelography is usually ordered when surgical treatment is considered. Since the advent of MRI, however, myelography is very rarely used. The MRI does not use ionizing radiation. Noninvasive, it produces excellent computerized images of soft tissues, such as seen in herniated discs and tumors. The MRI is based on nuclear magnetic resonance of atoms within the body; the atoms are generated by the use of radio waves. All these tests can reveal problems with the vertebrae, the disk, or the nerve itself.

Treatment

Pharmacological therapy—initial treatment for sciatica—focuses on pain relief. Regardless of the cause of the pain, analgesics (such as acetaminophen) may help relieve pain. Muscle relaxants are also used, but it hasn't been proved whether they really work. Furthermore, the side effects of muscle relaxants may be greater than their benefits, particularly in the elderly. Generally, pain relief is accomplished with nonsteroidal anti-inflammatory drugs (NSAIDs). It should be noted, however, that anti-inflammatory medications should be administered generally for only two to four weeks, and only if no medical contraindications are present. In 2001, the Food and Drug Administration (FDA) approved labeling two drugs for the relief of pain; they were an NSAID with selective cyclo-oxygenase 2 inhibition—rofecoxib (Vioxx)—and celecoxib (Celebrex). In 2004, Vioxx was withdrawn from the market by its manufacturer, Merck, because it was shown to double patients' risks of heart attack and stroke.

If the pain is unremitting, opioids may be prescribed for short-term use or a local anesthetic may be injected directly into the lower back. Massage and heat application may be suggested as adjunct therapies.

If the pain is chronic, different pain relief medications are used to avoid long-term dosing of NSAIDs, muscle relaxants, and opioids. Antidepressant drugs, which have been shown to be effective in treating pain, may be prescribed in conjunction with a short-term course of a muscle relaxants or a NSAID. Local anesthetic injections, or epidural steroids, are used in selected cases.

As pain permits, physical therapy is introduced into the treatment regime. Stretching exercises that focus on the lower back, buttocks, and hamstring muscles are suggested. The exercises may also include identifying and practicing comfortable, pain-reducing positions. Corsets and braces may be useful in some cases, but there is no clinical evidence for their general effectiveness. However, they may be helpful in the prevention of exacerbation of sciatica as related to certain activities.

With less pain and the success of early therapy, the patient is encouraged to follow a long-term exercise program to maintain a healthy back and prevent re-injury. A physical therapist may suggest exercises and regular activity, such as water exercise or walking. Patients are instructed in proper posture and body mechanics as means of minimizing symptoms during light lifting, prolonged sitting or standing, and other activities.

If the pain is chronic and conservative treatment fails—suggesting that a disk fragment has lodged in the spinal canal and is pressing on the nerve (and perhaps causing a loss of function—surgery may be required. A procedure to repair a herniated disk or excise part, or all of the piriformis muscle, may be suggested, particularly if there is neurologic evidence of nerve or nerve-root damage (radiculopathy). It should be noted, however, that newer and minimally invasive procedures are available to relieve the pain of sciatica. A local anesthetic is used, and surgery is performed on an ambulatory basis. The recovery period is two to six weeks.

Massage is a recommended form of therapy, especially when the sciatic pain arises from muscle spasm. Patients may be able to relieve symptoms by icing the painful area as soon as pain occurs. The physical therapist or nurse may instruct the patient to place ice on the affected area for 20 minutes, several times a day. After two to three days, a hot water bottle or heating pad can replace the ice. Chiropractic or osteopathic therapy may offer solutions for relieving pressure on the sciatic nerve and the accompanying pain. Acupuncture and biofeedback may also be useful as pain control methods.

Prognosis

Most cases of sciatica are treatable with pain medication and physical therapy. After four to six weeks of treatment, the patient should be able to resume normal activities.

Health care team roles

The diagnosis of sciatica is usually made by a PCP or a mid-level practitioner (physician assistant [PA] or nurse practitioner [NP]). Other physician specialists, such as neurologists, orthopedists, and physiatrists (specialists in physical medicine) also may provide consultative services. Radiologic technologists generally perform diagnostic imaging studies.

The treatment plan may involve physical therapists (PTs) and physical therapist assistants (PTAs), who instruct and supervise prescribed exercise programs. Patients also may be referred to specialists in orthotics, who prescribe appliances/apparatuses to support, align, prevent, or correct deformities, improve posture, or ease the function of movable body parts. Sometimes specialists work with ergonomics. The patient may be taught proper body mechanics at home and in the workplace.

Patient education

Patient education focuses on adhering to prescribed treatment, including exercise and body mechanics (above), and preventing future injuries. Nurses, PTs, PTAs, occupational therapists, and exercise physiologists may be involved in helping patients learn how to perform the activities of daily living (ADL) without exacerbating existing injuries.

Prevention

Some sources of sciatica are not preventable, such as disk degeneration, back strain resulting from pregnancy, or accidental injuries from falls. Other sources of back strain, such as poor posture, overexertion, obesity, or wearing high heels, may be corrected or avoided. Smoking may also predispose patients to pain, as it the supply of blood to invertebral discs, and interferes with healing. An orthopedist with the Gwinnett Health System in Lawrenceville, Georgia, Dr. Walker states that "Smoking leads to drying and stiffness of the discs, making them more susceptible to injury, including herniation, and prolonged recovery time."

KEY TERMS

Acupunture— The Chinese practice of piercing specific areas of the body along peripheral nerves with fine needles to relieve pain, to induce surgical anesthesia, and for therapeutic purposes.

Biofeedback— The process of furnishing an individual with information on the state of one or more physiologic variables, such as heart rate, blood pressure, or skin temperature. The goal is to enable the patient to gain some voluntary control over them.

Disk— Dense tissue between the vertebrae that acts as a shock absorber and prevents damage to nerves and blood vessels along the spine.

Electromyography— A diagnostic test in which a nerve's ability to conduct an impulse is measured.

Lumbosacral (LS)— Referring to the lower part of the backbone or spine.

Myelography— A medical test in which a special dye—a contrast medium—is injected the spinal subarachnoid space (through which cerebrospinal fluid [CSF] circulates, and across which extend delicate connective tissue pass) to make it visible on radiographic visualization.

NSAID— Nonsteroidal anti-inflammatory drugs are medications that produce analgesic and anti-inflammatory effects.

Opioid— A synthetic narcotic that has opiate-like qualities, but is not derived from opium.

Orthotics— Serving to protect or to restore or improve function; relating to the use or application of an orthosis.

Piriformis— A muscle in the pelvic girdle that is closely associated with the sciatic nerve.

Radiculopathy— A condition in which the nerve root of a nerve has been injured or damaged.

Spasm— Involuntary contraction of a muscle.

Spinal subarachnoid space— Space through which cerebrospinal fluid circulates, and across which extend delicate connective tissue pass.

Vertebrae— The component bones of the spine.

General suggestions for avoiding sciatica or preventing future episodes include sleeping on a firm mattress, using chairs with firm back supports, and sitting with both feet flat on the floor. Habitually crossing the legs while sitting may place excess pressure on the sciatic nerve. Sitting for prolonged periods of time also places pressure on the sciatic nerves, so patients are advised to take short breaks and move around during the workday, when on long trips, or in other situations that require sitting for extended lengths of time. When sitting for long periods, the patient should put his or her feet up on a low stool. If it is required that something be lifted without another person, the back should be kept straight and the legs should provide the lift. The knees should be bent, and the individual should get as close to the object as possible. This will reduce the load on the lower back. To give one a wider base of support and to distribute the weight of the object being lifted, the feet should be kept apart.

Regular exercise, such as swimming and walking, can build stamina, strengthen back muscles, improve flexibility, and improve posture. Exercise also helps to maintain proper body weight and lessens the likelihood of back strain.

Resources

BOOKS

Humes, H. David. Kelley's Textbook of Internal Medicine, 4th Edition. Philadelphia: Lippincott Williams & Wilkins, 2000, pp. 1336-1337.

Maigne, Robert. "Sciatica." In Diagnosis and Treatment of Pain of Vertebral Origin: A Manual Medicine Approach. Baltimore: Williams & Wilkins, 1996.

Pelletier, Kenneth R. Best Alternative Medicine: What Works? What Does Not? New York: Simon & Schuster, 2000, p. 372.

PERIODICALS

Douglas, Sara. "Sciatic Pain and Piriformis Syndrome." The Nurse Practitioner 22 (May 1997): 166.

ORGANIZATIONS

Gwinnett Coalition for Health and Human Services, 240 Oak Street, Lawrenceville, GA 30245. (770) 995-3339.

OTHER

American Academy of Orthopaedic Surgeons, "Your Orthopaedic Connection: Herniated Disk." 〈http://www.orthoinfo.aaos.org〉. Accessed June 28, 2001.

Edelson, Edward. "Infection is Linked to Sciatica." (June 21, 2001). 〈http://www.healthscout.com〉.

Marcus, Adam. "Study: Back Problems Are Inherited—Gene error raises risk of slipped disks." 〈http://www.healthscout.com〉. Accessed June 28, 2001.

Medscape dictionary online, Merriam-Webster. 〈http://www.dict.medscape.com〉. Accessed June 21, 2001.

Patel, Atul T. and Ogle A. "Diagnosis and Management of Acute Low Back Pain." American Family Physician (March 2000). 〈http://www.aafp.org〉.

Promina Doctors and Hospitals, "How to Lift Objects Safely." 〈http://www.promina.org〉. Accessed June 29, 2001.

Promina Doctors and Hospitals, "Minimize Your Risk of Back Pain." 〈http://www.promina.org〉. Accessed June 29, 2001.

Sciatica

Definition

Sciatica refers to pain or discomfort associated with the sciatic nerve. This nerve runs from the lower part of the spinal cord, down the back of the leg, to the foot. Injury to or pressure on the sciatic nerve can cause the characteristic pain of sciatica: a sharp or burning pain that radiates from the lower back or hip, possibly following the path of the sciatic nerve to the foot.

Description

The sciatic nerve is the largest and longest nerve in the body. About the thickness of a person's thumb, it spans from the lower back to the foot. The nerve originates in the lower part of the spinal cord, the so-called lumbar region. As it branches off from the spinal cord, it passes between the bony vertebrae (the component bones of the spine) and runs through the pelvic girdle, or hip bones. The nerve passes through the hip joint and continues down the back of the leg to the foot.

Sciatica is a fairly common disorder and approximately 40% of the population experiences it at some point in their lives. However, only about 1% have coexisting sensory or motor deficits. Sciatic pain has several root causes and treatment may hinge upon the underlying problem.

Of the identifiable causes of sciatic pain, lumbosacral radiculopathy and back strain are the most frequently suspected. The term lumbosacral refers to the lower part of the spine, and radiculopathy describes a problem with the spinal nerve roots that pass between the vertebrae and give rise to the sciatic nerve. This area between the vertebrae is cushioned with a disk of shock-absorbing tissue. If this disk shifts or is damaged through injury or disease, the spinal nerve root may be compressed by the shifted tissue or the vertebrae.

This compression of the nerve roots sends a pain signal to the brain. Although the actual injury is to the

nerve roots, the pain may be perceived as coming from anywhere along the sciatic nerve.

The sciatic nerve can be compressed in other ways. Back strain may cause muscle spasms in the lower back, placing pressure on the sciatic nerve. In rare cases, infection, cancer , bone inflammation, or other diseases may be causing the pressure. More likely, but often overlooked, is the piriformis syndrome. As the sciatic nerve passes through the hip joint, it shares the space with several muscles. One of these muscles, the piriformis muscle, is closely associated with the sciatic nerve. In some people, the nerve actually runs through the muscle. If this muscle is injured or has a spasm, it places pressure on the sciatic nerve, in effect, compressing it.

In many sciatica cases, the specific cause is never identified. About half of affected individuals recover from an episode within a month. Some cases can linger a few weeks longer and may require aggressive treatment. In some cases, the pain may return or potentially become chronic.

Demographics

A common disorder, sciatica affects about 40 percent of the population. It is found more frequently in people 30 to 50 years old, but occurs often in the elderly due to degenerative spinal disorders. Most often, sciatica is seen as a result of general wear and tear on the lower lumbosacral spine.

Causes and symptoms

Causes

The most common cause of sciatic pain is pressure on the nerves in the lumbosacral spine. Injury to the pelvis or other trauma can cause sciatica. However, it is most often a disc (a pad of shock-absorbing tissue between each vertebra) that bulges or is herniated, usually near the L4 or L5, and presses on the sciatic nerve and causes pain, numbness, or tingling. This is often called a slipped disc. Degenerative disc disease, a condition where the discs begin to break down or crumble, can irritate the nerves, too. Sometimes, a disc may rupture, causing a jelly-like substance to seep out and press on the sciatic nerve. A bulging disc can form slowly over time. A ruptured disc may be caused by an injury, bone spurs growing from the spine, or aging.

Spondylolisthesis, a condition when one vertebra slips forward over another, can press against the sciatic nerve. This action is similar to a slipped disc, except here it is a vertebra that has moved. Spondylolisthesis is the result of degenerative disc disease.

Back strain can cause the muscles in the lower back to spasm and swell. This can also put pressure against the sciatic nerve.

Some medical disorders can also cause sciatic pain. Lumbar spinal stenosis , a narrowing of the spinal canal, is found in adults over 60 years old. This condition can put pressure on the sciatic nerve. Other diseases that can cause sciatica are spinal arthritis, diabetes, and cancer.

Pregnancy can also cause sciatic pain. The growing fetus can shift internal structures so that pressure is placed on the sciatic nerve.

Other conditions such as sacroiliac joint dysfunction or piriformis syndrome can mimic sciatica symptoms, but are not actually sciatica. An irritation of the sacroiliac joint can irritate the nerve at L5 and can cause sciatic-like pain. Piriformis syndrome is a spasm of the piriformis muscle that is located near the sciatic nerve. In some cases, the sciatic nerve runs through the muscle itself. If the piriformis muscle is injured or spasms, it can press against the sciatic nerve. Runners, race walkers, and people who sit for long periods can experience piriformis syndrome.

In a number of cases, no specific cause for the sciatic pain or numbness is discovered.

Symptoms

Pain is the most pronounced symptom of sciatica. It is often accompanied by numbness or a burning or tingling sensation. Often, the pain is felt even during sitting, but may be more pronounced when attempting to stand. Some patients feel pain increase when they walk any distance.

Where that pain is felt, however, is largely a factor of where the sciatic nerve is compressed. Each region affects different parts of the lower extremities and produces characteristic symptoms.

If the nerve is affected in the region of L3-L4, the patient will have pain and/or numbness in the lower leg and foot and can have problems trying to walk on the heel of the foot. The patient may also have reduced knee-jerk reflex.

A sciatic nerve compression near L4-L5 results in pain and/or numbness in the top of the foot, especially near the area between the big toe and the second toe. The patient may present with weakness in the ankle that causes the foot to drop or drag.

Patients who have sciatic compression near L5-S1 experience pain and/or numbness in the outside regions of the foot. The patient has reduced ankle-jerk reflex and has trouble walking on tip toe.

Pressure on the sacral nerves from sacroiliac joint dysfunction produces a deep ache inside the leg, rather than pain in a specific area as in true sciatica. Piriformis syndrome causes pain or numbness most commonly in the buttocks and can radiate downward, mimicking true sciatica.

Diagnosis

Before treating sciatic pain, as much information as possible is collected. The individual is asked to recount the location and nature of the pain, how long it has continued, and any accidents or unusual activities prior to its onset. This information provides clues that may point to back strain or injury to a specific location. Back pain from disk disease, piriformis syndrome, and back strain must be differentiated from more serious conditions such as cancer or infection. Lumbar stenosis, an overgrowth of the covering layers of the vertebrae that narrows the spinal canal, must also be considered. The possibility that a difference in leg lengths is causing the pain should be evaluated; the problem can be easily be treated with a foot orthotic or built-up shoe.

Often, a straight-leg-raising test is done, in which the person lies face upward and the health-care provider raises the affected leg to various heights. This test pinpoints the location of the pain and may reveal whether it is caused by a disk problem. Other tests, such as having the individual rotate the hip joint, assess the hip muscles. Any pain caused by these movements may provide information about involvement of the piriformis muscle, and piriformis weakness is tested with additional leg-strength maneuvers.

Further tests may be done depending on the results of the physical examination and initial pain treatment. Such tests might include magnetic resonance imaging (MRI) and computed tomography scans (CT scans ). Other tests examine the conduction of electricity through nerve tissues, and include studies of the electrical activity generated as muscles contract (electromyography), nerve conduction velocity, and evoked potential testing. A more invasive test involves injecting a contrast substance into the space between the vertebrae and making x-ray images of the spinal cord (myelography), but this procedure is usually done only if surgery is being considered. All of these tests can reveal problems with the vertebrae, the disk, or the nerve itself.

Treatment

Returning the patient to mobility and independence is the goal of treatment. Since pain must be managed before further options are considered, the doctor will prescribe over-the-counter NSAIDS (non-steroidal anti-inflammatory drugs ) such as naproxen and ibuprofen. Oral steroids may also be prescribed for herniated discs. Muscle relaxants may be prescribed, especially for piriformis syndrome.

If a patient is in severe pain, the doctor may inject steroids directly into the area around the sciatic nerve. This decreases inflammation and offers temporary pain relief. Some patients experience relief for up to a year; others are pain-free for a week. Though this procedure does not work for everyone, it can be necessary relief for the patient to be able to complete the physical therapy necessary for recovery.

Bed rest is discouraged, though the doctor may recommend frequent rest periods when the patient can apply heat to the lower back to treat the inflammation of sciatica. Moist heat is the most effective.

The doctor may also begin to treat any underlying condition that may have caused or contributed to the bout of sciatica. Depending on the cause, specific treatment may be postponed until the current sciatic episode has passed.

Once the pain is under control, the doctor often will refer the patient to a physical therapist for a regime of exercise and education specific to the patient's type of sciatica. Ultrasound, transcutaneous electrical stimulation (TENs), biofeedback , and deep tissue massage may also be ordered by the physical therapist.

Braces, splints, or orthopedic shoes may help some patients accommodate for lost impairment. However, these are not permanent solutions. They may help a patient continue to work or go about daily activities until they can strengthen the muscles necessary to support the back.

Occupational therapy may also be helpful to educate patients about proper body alignment when doing daily tasks or work requirements. Other behavioral education may be necessary.

Surgery is only used in extreme cases when the sciatic nerve creates significant weakness or loss of bladder or bowels. However, surgery (diskectomy) is often used to remove part of a herniated disc. This procedure can be done with a microscope (microdisketomy). Surgery for degenerative disc disease does not stop the progression of this disease; it merely relieves the immediate problem. A study in 2007 reported that though disc surgery patients may receive immediate relief, they had similar positive outcomes a year later as those of patients who chose conservative treatment over surgery.

Alternative treatments

The doctor may also recommend alternative treatments to help a patient either manage the pain or treat the underlying cause.

Acupuncture is the Eastern practice of balancing the body's natural energies by inserting thin sterilized needles into specific parts of the body. The procedure is relatively painless, and many patients experience peaceful relaxation during the process. The National Institutes of Health has noted that acupuncture is effective in relieving the pain of sciatica and other back discomfort.

QUESTIONS TO ASK YOUR DOCTOR

• What is the cause of my sciatica pain?
• What can be done to treat that condition?
• What tests will I have to take?
• How long will I need to take pain medication?
• What can I expect from the physical therapist?
• What alternative treatments do you recommend?
• What home care do you suggest?
• How long before I can go back to my regular activities?
• Will I have to have surgery?

Though massage cannot help remove the pressure of a disc against the sciatic nerve, it can relax tense muscles in the lower back and buttocks and stimulate blood flow. This is especially helpful for patients suffering from piriformis syndrome. Massage also is relaxing and can help release endorphins, the body's natural pain relievers.

Chiropractic manipulations can help align the spine. They may be helpful for some disc problems.

Further, yoga has been found to be useful for keeping the muscles stretched and the spine flexible. However, care may need to be taken regarding some postures that put stress on the lower back. Those include any type of sitting cross legged or extreme stretches of the spine.

Nutrition/Dietetic concerns

There are no dietietic concerns regarding sciatica.

Therapy

Physical therapy is essential to successful recovery from sciatica. Inactivity, especially bed rest, has been found to make sciatic pain worse. Consistent movement keeps the body supple and strengthens critical muscles that support the lower back and legs. Walking and swimming, including pool therapy, are essential long-term exercises necessary to prevent sciatica recurrence.

Prognosis

Most cases of sciatica are treatable with pain medication and physical therapy. After 4–6 weeks of treatment, an individual should be able to resume normal activities.

KEY TERMS

Disc —A tissue between two vertebrae that cushions the spine.

Diskectomy —Surgery to remove part of a herniated disc.

CT —Computerized tomography, a test that uses a dye and a computer to image parts of the body

Coccyx —The tail bone or last four vertebrae of the spine.

Electromyography —An electrical activity test of the nerves and muscles.

Lumbosacral spine —The lower portion of the spine, including the sacrum and the coccyx.

MRI —Magnetic resonance imaging, a test that uses magnets to film parts of the body.

Microdisketomy —Adisketomyusing a microscope.

Piriformis —A muscle in the pelvic area near the sciatic nerve.

Radicuolpathy —Another name for sciatica.

Sciatic nerve —The largest and longest nerve in the body, running from the lower back to the foot.

Spondylolisthesis —A condition when one vertebra slips forward over another.

Vertebrae —Structures that compose the spine that protect the spinal chord.

Prevention

Some sources of sciatica are not preventable, such as disk degeneration, back strain due to pregnancy, or accidental falls . Other sources of back strain, such as poor posture, overexertion, being overweight, or wearing high heels, can be corrected or avoided. Cigarette smoking may also predispose people to pain, and should be discontinued.

General suggestions for avoiding sciatica, or preventing a repeat episode, include sleeping on a firm mattress, using chairs with firm back support, and sitting with both feet flat on the floor. Habitually crossing the legs while sitting can place excess pressure on the sciatic nerve. Sitting a lot can also place pressure on the sciatic nerves, so it's a good idea to take short breaks and move around during the work day, long trips, or any other situation that requires sitting for an extended length of time. If lifting is required, the back should be kept straight and the legs should provide the lift. Regular exercise, such as swimming and walking, can strengthen back muscles and improve posture. Exercise can also help maintain a healthy weight and lessen the likelihood of back strain.

Caregiver concerns

Special care should be taken to determine the underlying cause of sciatica and to treat that as well as the presenting symptoms.

Resources

periodicals

Barry, Henry. “Bed rest is bad for back pain, ineffective for sciatica.” American Family Physician (July 2005):329

Gupta, Sanjay. “Two fixes for bad backs.” Time (July 2007):74 “How can I treat sciatica.” Natural Health. (October 2006:30

Markova, Tsveti; Dhilion, Baldev Singh, and Martin, Sandra. “Treatment of acure sciatica.” American Family Physician. (January 2007):99-100

“Observation is an option for patients with sciatica >6 weeks.” Journal of Family Practice. (September 2007):704

other

“Sciatica” Mayo Clinic. 2008. http://www.mayoclinic.com/health/sciatica/DS00516

Eidelson, Stewart G. “Sciatic Nerve and Sciatica.” Spine Universe 2008. http://www.spineuniverse.com/displayarticle.php/article2524.html

“Sciatica.” Medline Plus 2008. http://www.nlm.nih.gov/medlineplus/ency/article/000686.htm

“Sciatica.” eMedicineHealth 2008. http://www.emedicine-health.com/script/main/art.asp?articlekey=59259&pf=3&page=1

other

Spine Health. http://www.spine-health.com

organizations

American Academy of Orthopaedic Surgeons, 6300 North River Rd, Rosemont, IL, 60018-4262, 847-823-7186, 800-346-2267, 847-823-8125, http://www.aaos.org.

Janie F. Franz

Sciatica

Definition

Sciatica refers to pain or discomfort associated with the sciatic nerve. This nerve runs from the lower part of the spinal cord down the back and side of the leg to the foot. Injury to or pressure on the sciatic nerve can cause the characteristic pain of sciatica: a sharp or burning pain or even numbness that radiates from the lower back or hip, possibly following the path of the sciatic nerve to the foot.

Description

The sciatic nerve is the largest and longest nerve in the body. About the thickness of a person's thumb, it spans from the lower back to the foot. The nerve originates in the lower part of the spinal cord, the so-called lumbar region. As the sciatic nerve branches off from the spinal cord, it passes between the bony vertebrae (the component bones of the spine) and runs through the pelvic girdle, or hip bones, and the buttock area. The nerve passes through the hip joint and continues down the back and side of the leg to the foot.

Sciatica is a fairly common disorder, approximately 40% of the population experiences it at some point in their lives. However, only about 1% have coexisting sensory or motor deficits. Sciatic pain has several root causes and treatment may hinge upon the underlying problem.

Of the identifiable causes of sciatic pain, lumbosacral radiculopathy and back strain are the most frequently suspected. The term lumbosacral refers to the lower part of the spine, and radiculopathy describes a problem with the spinal nerve roots that pass between the vertebrae and give rise to the sciatic nerve. This area between the vertebrae is cushioned with a disk of shock-absorbing tissue. If this disk shifts or is damaged through injury or disease, the spinal nerve root may be compressed by the shifted tissue or the vertebrae.

This compression of the nerve roots sends a pain signal to the brain. Although the actual injury is to the nerve roots, the pain may be perceived as coming from any point along the sciatic nerve.

The sciatic nerve can be compressed in other ways. Back strain may cause muscle spasms in the lower back, placing pressure on the sciatic nerve. In rare cases, infection, cancer , bone inflammation, or other diseases may cause the pressure. More likely, but often overlooked, is the piriformis syndrome. As the sciatic nerve passes through the hip joint, it shares the space with several muscles. One of these muscles, the piriformis muscle, is closely associated with the sciatic nerve. In some people, the nerve actually runs through the muscle. If this muscle is injured or has a spasm, it places pressure on the sciatic nerve—in effect, compressing it.

In many sciatica cases, the specific cause is never identified. About half of affected individuals recover from an episode within a month. Some cases can linger a few weeks longer and may require aggressive treatment. In other cases, the pain may return or potentially become chronic.

Causes & symptoms

Persons with sciatica may experience some lower back pain, but the most common symptom is pain that radiates through one buttock and down the back of the adjoining leg. The most identified cause of the pain is compression or pressure on the sciatic nerve. The extent of the pain varies among individuals. Some people describe pain that centers in the area of the hip, and others perceive discomfort all the way to the foot. The quality of the pain also varies; it may be described as tingling, burning, prickly, aching, or stabbing.

Onset of sciatica can be sudden, but it can also develop gradually. The pain may be intermittent or continuous. Certain activities, such as bending, coughing, sneezing , or sitting, may make the pain worse.

Chronic pain may arise from more than just compression on the nerve. According to some pain researchers, physical damage to a nerve is only half of the equation. A recent theory proposes that some nerve injuries result in a release of neurotransmitters and immune system chemicals that enhance and sustain a pain message. Even after the injury has healed or the damage has been repaired, the pain continues. Control of this abnormal type of pain is difficult.

Diagnosis

Before treating sciatic pain, as much information as possible must be collected. The individual is asked to recount the location and nature of the pain, how long it has continued, and any accidents or unusual activities prior to its onset. This information provides clues that may

point to back strain or injury to a specific location. Back pain from disk disease, piriformis syndrome, and back strain must be differentiated from more serious conditions such as cancer or infection. Lumbar stenosis, an overgrowth of the covering layers of the vertebrae that narrows the spinal canal, must also be considered. The possibility that a difference in leg lengths is causing the pain should be evaluated; the problem can be easily be treated with a foot orthotic or built-up shoe.

Often, a straight-leg-raising test is done, in which the person lies face upward and the healthcare provider raises the affected leg to various heights. This test pinpoints the location of the pain and may reveal whether it is caused by a disk problem. Other tests, such as having the individual rotate the hip joint, assess the condition of the hip muscles. Any pain caused by these movements may provide information about involvement of the piriformis muscle, and piriformis weakness is tested with additional leg-strength maneuvers.

Further tests may be done depending on the results of the physical examination and initial pain treatment. Such tests might include magnetic resonance imaging (MRI) and computed tomography (CT) scans. Other tests examine the conduction of electricity through nerve tissues, and include studies of the electrical activity generated as muscles contract (electromyography), nerve conduction velocity, and evoked potential testing. A more invasive test involves injecting a contrast substance into the space between the vertebrae and making x-ray images of the spinal cord (myelography), but this procedure is usually done only if surgery is being considered as an option. All of these tests can reveal problems with the vertebrae, the disk, or the nerve itself.

Treatment

Massage is a recommended form of therapy, especially if the sciatic pain arises from muscle spasm. Symptoms may also be relieved by icing the painful area as soon as the pain occurs. Ice should be left on the area for 30–60 minutes several times a day. After two or three days, a hot water bottle or heating pad can replace the ice. Chiropractic or osteopathy may offer possible solutions for relieving pressure on the sciatic nerve and alleviating the accompanying pain. Biofeedback may also be useful as a pain control method. Bodywork, such as the Alexander technique , can assist an individual in improving posture and preventing further episodes of sciatic pain.

Acupuncture is another alternative approach that appears to offer relief to many persons with sciatica, as indicated by several clinical trials in the United States and Europe. The World Health Organization (WHO) lists sciatica as one of 40 conditions for which acupuncture is recognized as an appropriate complementary treatment.

Practitioners of Ayurvedic medicine regard sciatica as a disorder resulting from an imbalance in vata, one of three doshas or energies in the human body. The traditional Ayurvedic treatment for vata disorders is vasti, or administration of an oil-based enema to cleanse the colon. An Ayurvedic herbal preparation that is used to treat sciatica is made from the leaves of Nyctanthes arbor tristis, which is also known as Parijat or "sad tree." A recent study of an alcohol-based extract of this plant indicates that it is effective as a tranquilizer and local anesthetic, which supports its traditional Ayurvedic use.

Western herbalists typically treat sciatica with valerian root to relax the muscle spasms that often accompany sciatica, and with white willow bark for pain relief.

Homeopathic remedies for sciatica include Ruta graveolens, Colocynth (for sciatic pain that is worse in cold or damp weather), or Magnesium phosphoric (for lightning-like pains that are soothed by heat and made worse by coughing).

Allopathic treatment

Initial treatment for sciatica focuses on pain relief. For acute or very painful flare-ups, bed rest is advised for up to a week in conjunction with medication for the pain. Pain medication includes acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin, or muscle relaxants. If the pain is unremitting, opioids may be prescribed for short-term use, or a local anesthetic will be injected directly into the lower back. Massage and heat application may be suggested as adjuncts.

If the pain is chronic, different pain relief medications are used to avoid long-term dosing of NSAIDs, muscle relaxants, and opioids. Antidepressant drugs, which have been shown to be effective in treating pain, may be prescribed alongside short-term use of muscle relaxants or NSAIDs. Local anesthetic injections or epidural steroids are used in selected cases.

As the pain allows, physical therapy is introduced into the treatment regime. Stretching exercises that focus on the lower back, buttock, and hamstring muscles are suggested. The exercises also include finding comfortable, pain-reducing positions. Corsets and braces may be useful in some cases, but evidence for their general effectiveness is lacking. However, they may be helpful to prevent exacerbations related to certain activities.

With less pain and the success of early therapy, the individual is encouraged to follow a long-term program to maintain a healthy back and prevent re-injury. A physical therapist may suggest exercises and regular activity, such as water exercise or walking. Patients are instructed in proper body mechanics to minimize symptoms during light lifting or other activities.

If the pain is chronic and conservative treatment fails, surgery to repair a herniated disk or to cut out part or all of the piriformis muscle may be suggested, particularly if there is evidence of nerve or nerve-root damage.

A new minimally invasive surgical treatment for sciatica was introduced in 2002. It is known as microscopically assisted percutaneous nucleotomy, or MAPN. MAPN allows the surgeon to repair a herniated disk with less damage to surrounding tissues; it shortens the patient's recovery time and relieves the pain of sciatica as effectively as more invasive surgical procedures.

Expected results

Most cases of sciatica are treatable with pain medication and physical therapy. After four to six weeks of treatment, an individual should be able to resume normal activities.

Prevention

Some sources of sciatica are not preventable, such as disk degeneration, back strain due to pregnancy , or accidental falls. Other sources of back strain, such as poor posture, overexertion, being overweight, or wearing high heels, can be corrected or avoided. Cigarette smoking may also predispose people to pain, and should be discontinued with the onset of pain.

General suggestions for avoiding sciatica or preventing a repeat episode include sleeping on a firm mattress; using chairs with firm back support; and sitting with both feet flat on the floor. Habitually crossing the legs while sitting can place excess pressure on the sciatic nerve. Sitting for long periods of time can also place pressure on the sciatic nerves, so it is recommended to take short breaks and move around during the work day, during long trips, or in other situations that require sitting for extended periods of time. If lifting is required, the back should be kept straight and the legs should provide the lift. Regular exercise, such as swimming and walking, can strengthen back muscles and improve posture. Exercise can also help maintain a healthy weight and lessen the likelihood of back strain.

Resources

BOOKS

Maigne, Robert. "Sciatica." In Diagnosis and Treatment of Pain of Vertebral Origin: A Manual Medicine Approach. Baltimore: Williams & Wilkins, 1996.

Pelletier, Kenneth R., MD. The Best Alternative Medicine, Part II, "CAM Therapies for Specific Conditions: Sciatica." New York: Simon & Schuster, 2002.

Rydevik, Björn, Mitsuo Hasue, and Peter Wehling. Etiology of Sciatic Pain and Mechanisms of Nerve Root Compression, vol. 1: The Lumbar Spine, 2d ed., edited by Sam W. Wiesel, et al. Philadelphia: W.B. Saunders Company, 1996.

PERIODICALS

Chiodo, A., and A. J. Haig. "Lumbosacral Radiculopathies: Conservative Approaches to Management." Physical Medicine and Rehabilitation Clinics of North America 13 (August 2002): 609-621.

Douglas, Sara. "Sciatic Pain and Piriformis Syndrome." The Nurse Practitioner 22 (May 1997): 166.

Greiner-Perth, R., H. Bohm, and H. El Saghir. "Microscopically Assisted Percutaneous Nucleotomy, An Alternative Minimally Invasive Procedure for the Operative Treatment of Lumbar Disc Herniation: Preliminary Results." Neurosurgical Review 25 (August 2002): 225-227.

Parziale, John R., Thomas H. Hudgins, and Loren M. Fishman. "The Piriformis Syndrome." The American Journal of Orthopedics (December 1996): 819.

Saxena, R. S., B. Gupta, and S. Lata. "Tranquilizing, Antihistaminic and Purgative Activity of Nyctanthes arbor tristis Leaf Extract." Journal of Ethnopharmacology 81 (August 2002): 321-325.

Wheeler, Anthony H. "Diagnosis and Management of Low Back Pain and Sciatica." American Family Physician (October 1995): 1333.

ORGANIZATIONS

American Academy of Medical Acupuncture (AAMA). 4929 Wilshire Blvd., Suite 428, Los Angeles, CA 90010. (323) 937-5514. <www.medicalacupuncture.org>.

American Academy of Orthopaedic Surgeons (AAOS). 6300 North River Road, Rosemont, IL 60018. (847) 823-7186 or (800) 346-AAOS. <www.aaos.org>.

American Physical Therapy Association (APTA). 1111 North Fairfax Street, Alexandria, VA 22314. (703) 684-APTA or (800) 999-2782. <www.apta.org>.

National Center for Homeopathy. 801 North Fairfax Street, Alexandria, VA 22314. (703) 548-7790. <www.homeopathic.org>.

National Institute of Ayurvedic Medicine. 584 Milltown Road, Brewster, NY 10509. (845) 278-8700. <www.niam.com>.

Kathleen Wright

Rebecca J. Frey, PhD

Sciatica

Definition

Sciatica refers to pain or discomfort associated with the sciatic nerve. This nerve runs from the lower part of the spinal cord, down the back of the leg, to the foot. Injury to or pressure on the sciatic nerve can cause the characteristic pain of sciatica: a sharp or burning pain that radiates from the lower back or hip, possibly following the path of the sciatic nerve to the foot.

Description

The sciatic nerve is the largest and longest nerve in the body. About the thickness of a person's thumb, it spans from the lower back to the foot. The nerve originates in the lower part of the spinal cord, the so-called lumbar region. As it branches off from the spinal cord, it passes between the bony vertebrae (the component bones of the spine) and runs through the pelvic girdle, or hip bones. The nerve passes through the hip joint and continues down the back of the leg to the foot.

Sciatica is a fairly common disorder and approximately 40% of the population experiences it at some point in their lives. However, only about 1% have coexisting sensory or motor deficits. Sciatic pain has several root causes and treatment may hinge upon the underlying problem.

Of the identifiable causes of sciatic pain, lumbosacral radiculopathy and back strain are the most frequently suspected. The term lumbosacral refers to the lower part of the spine, and radiculopathy describes a problem with the spinal nerve roots that pass between the vertebrae and give rise to the sciatic nerve. This area between the vertebrae is cushioned with a disk of shockabsorbing tissue. If this disk shifts or is damaged through injury or disease, the spinal nerve root may be compressed by the shifted tissue or the vertebrae.

This compression of the nerve roots sends a pain signal to the brain. Although the actual injury is to the nerve roots, the pain may be perceived as coming from anywhere along the sciatic nerve.

The sciatic nerve can be compressed in other ways. Back strain may cause muscle spasms in the lower back, placing pressure on the sciatic nerve. In rare cases, infection, cancer, bone inflammation, or other diseases may be causing the pressure. More likely, but often overlooked, is the piriformis syndrome. As the sciatic nerve passes through the hip joint, it shares the space with several muscles. One of these muscles, the piriformis muscle, is closely associated with the sciatic nerve. In some people, the nerve actually runs through the muscle. If this muscle is injured or has a spasm, it places pressure on the sciatic nerve, in effect, compressing it.

In many sciatica cases, the specific cause is never identified. About half of affected individuals recover from an episode within a month. Some cases can linger a few weeks longer and may require aggressive treatment. In some cases, the pain may return or potentially become chronic.

Causes and symptoms

Individuals with sciatica may experience some lower back pain, but the most common symptom is pain that radiates through one buttock and down the back of that leg. The most identified cause of the pain is compression or pressure on the sciatic nerve. The extent of the pain varies between individuals. Some people describe pain that centers in the area of the hip, and others perceive discomfort all the way to the foot. The quality of the pain also varies; it may be described as tingling, burning, prickly, aching, or stabbing.

Onset of sciatica can be sudden, but it can also develop gradually. The pain may be intermittent or continuous, and certain activities, such as bending, coughing, sneezing, or sitting, may make the pain worse.

Chronic pain may arise from more than just compression on the nerve. According to some pain researchers, physical damage to a nerve is only half of the equation. A developing theory proposes that some nerve injuries result in a release of neurotransmitters and immune system chemicals that enhance and sustain a pain message. Even after the injury has healed, or the damage has been repaired, the pain continues. Control of this abnormal type of pain is difficult.

Diagnosis

Before treating sciatic pain, as much information as possible is collected. The individual is asked to recount the location and nature of the pain, how long it has continued, and any accidents or unusual activities prior to its onset. This information provides clues that may point to back strain or injury to a specific location. Back pain from disk disease, piriformis syndrome, and back strain must be differentiated from more serious conditions such as cancer or infection. Lumbar stenosis, an overgrowth of the covering layers of the vertebrae that narrows the spinal canal, must also be considered. The possibility that a difference in leg lengths is causing the pain should be evaluated; the problem can be easily be treated with a foot orthotic or built-up shoe.

Often, a straight-leg-raising test is done, in which the person lies face upward and the health-care provider raises the affected leg to various heights. This test pinpoints the location of the pain and may reveal whether it is caused by a disk problem. Other tests, such as having the individual rotate the hip joint, assess the hip muscles. Any pain caused by these movements may provide information about involvement of the piriformis muscle, and piriformis weakness is tested with additional leg-strength maneuvers.

Further tests may be done depending on the results of the physical examination and initial pain treatment. Such tests might include magnetic resonance imaging (MRI) and computed tomography scans (CT scans). Other tests examine the conduction of electricity through nerve tissues, and include studies of the electrical activity generated as muscles contract (electromyography ), nerve conduction velocity, and evoked potential testing. A more invasive test involves injecting a contrast substance into the space between the vertebrae and making x-ray images of the spinal cord (myelography ), but this procedure is usually done only if surgery is being considered. All of these tests can reveal problems with the vertebrae, the disk, or the nerve itself.

Treatment

Initial treatment for sciatica focuses on pain relief. For acute or very painful flare-ups, bed rest is advised for up to a week in conjunction with medication for the pain. Pain medication includes acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin, or muscle relaxants. If the pain is unremitting, opioids may be prescribed for short-term use or a local anesthetic will be injected directly into the lower back. Massage and heat application may be suggested as adjuncts.

If the pain is chronic, different pain relief medications are used to avoid long-term dosing of NSAIDs, muscle relaxants, and opioids. Antidepressant drugs, which have been shown to be effective in treating pain, may be prescribed alongside short-term use of muscle relaxants or NSAIDs. Local anesthetic injections or epidural steroids are used in selected cases.

As the pain allows, physical therapy is introduced into the treatment regime. Stretching exercises that focus on the lower back, buttock, and hamstring muscles are suggested. The exercises also include finding comfortable, pain-reducing positions. Corsets and braces may be useful in some cases, but evidence for their general effectiveness is lacking. However, they may be helpful to prevent exacerbations related to certain activities.

With less pain and the success of early therapy, the individual is encouraged to follow a long-term program to maintain a healthy back and prevent re-injury. A physical therapist may suggest exercises and regular activity, such as water exercise or walking. Patients are instructed in proper body mechanics to minimize symptoms during light lifting or other activities.

If the pain is chronic and conservative treatment fails, surgery to repair a herniated disk or cut out part or all of the piriformis muscle may be suggested, particularly if there is neurologic evidence of nerve or nerve-root damage.

Alternative treatment

Massage is a recommended form of therapy, especially if the sciatic pain arises from muscle spasm. Symptoms may also be relieved by icing the painful area as soon as the pain occurs. Ice should be left on the area for 30-60 minutes several times a day. After 2-3 days, a hot water bottle or heating pad can replace the ice. Chiropractic or osteopathy may offer possible solutions for relieving pressure on the sciatic nerve and the accompanying pain. Acupuncture and biofeedback may also be useful as pain control methods. Body work, such as the Alexander technique, can assist an individual in improving posture and preventing further episodes of sciatic pain.

Prognosis

Most cases of sciatica are treatable with pain medication and physical therapy. After 4-6 weeks of treatment, an individual should be able to resume normal activities.

Prevention

Some sources of sciatica are not preventable, such as disk degeneration, back strain due to pregnancy, or accidental falls. Other sources of back strain, such as poor posture, overexertion, being overweight, or wearing high heels, can be corrected or avoided. Cigarette smoking may also predispose people to pain, and should be discontinued.

General suggestions for avoiding sciatica, or preventing a repeat episode, include sleeping on a firm mattress, using chairs with firm back support, and sitting with both feet flat on the floor. Habitually crossing the legs while sitting can place excess pressure on the sciatic nerve. Sitting a lot can also place pressure on the sciatic nerves, so it's a good idea to take short breaks and move around during the work day, long trips, or any other situation that requires sitting for an extended length of time. If lifting is required, the back should be kept straight and the legs should provide the lift. Regular exercise, such as swimming and walking, can strengthen back muscles and improve posture. Exercise can also help maintain a healthy weight and lessen the likelihood of back strain.

Resources

PERIODICALS

Douglas, Sara. "Sciatic Pain and Piriformis Syndrome." The Nurse Practitioner 22 (May 1997): 166.

KEY TERMS

Disk— Dense tissue between the vertebrae that acts as a shock absorber and prevents damage to nerves and blood vessels along the spine.

Electromyography— A medical test in which a nerve's ability to conduct an impulse is measured.

Lumbosacral— Referring to the lower part of the backbone or spine.

Myelography— A medical test in which a special dye is injected into a nerve to make it visible on an x ray.

Piriformis— A muscle in the pelvic girdle that is closely associated with the sciatic nerve.

Radiculopathy— A condition in which the spinal nerve root of a nerve has been injured or damaged.

Spasm— Involuntary contraction of a muscle.

Vertebrae— The component bones of the spine.

Sciatica

Definition

Sciatica is pain in the lower back that can radiate down the buttocks and leg and occasionally into the foot. The pain is a result of inflammation of the sciatic nerve, usually from a herniated vertebral disk, although other causes are common. Sciatica is one of the frequently reported causes of lower back pain .

Description

Sciatica, also known as lumbago or lumbar radiculopathy , causes pain as a result of pressure on the sciatic nerve. The sciatic nerve is formed from lumbar roots that emerge from the spinal column. It rises into the pelvis, and travels down the buttocks, the leg, and into the foot. Occurring on both the left and right side of the body, these nerves are the largest in the body, with a diameter as great as a finger; they branch at several points along their path. Sciatica occurs when these nerves become irritated, most often because of a herniated vertebral disk that puts pressure on the sciatic nerve as it emerges from the spinal column.

Sciatica causes pain that may be constant or intermittent and it may include numbness, burning, or tingling. Coughing, sneezing, bending over, or lifting heavy objects may increase the pain. In some cases, there is weakening of muscles in the buttocks, legs, and/or feet.

Demographics

Sciatica is one of the most common forms of back pain. It occurs in about 5% of people who visit their doctor for back pain and in 1–3% of the general adult population. It is most common in people who are between 30 and 50 years of age, as those are the ages most prone to herniating vertebral disks. After age 30, the tough exterior of the vertebral disks undergoes a natural thinning, making it easier for the gel-like inner core to rupture it. After the age of 50, the interior of the vertebral disk becomes slightly hardened, making it less likely to protrude out.

Causes and symptoms

Pressure on the sciatic nerve can result from poor posture, muscle strain, pregnancy, wearing high heels, or being overweight. A herniated disk in the lumbar spine is the most common cause of sciatica. Herniated disks occur when the gel-like inner core of a vertebral disk (nucleus puposus ) ruptures through the tougher outer section (annulus ) of the disk. This extrusion puts pressure on the nerve root, causing it to function improperly. Another common cause of sciatica is lumbar spinal stenosis, or narrowing of the spinal canal, which puts pressure on the roots making up the sciatic nerve. Degenerative disk disease causes sciatica when the disk weakens enough to allow excessive movement of the vertebrae near the sciatic nerve. In addition, the degenerated disk may leak irritating proteins in the vicinity of the nerve. Although isthmic spondylolisthesis is relatively common in adults, it only occasionally causes sciatica. This occurs when a vertebra develops a stress fracture and slips, slightly impinging on the sciatic nerve as it exits the spine. Piriformis syndrome causes sciatica when the sciatic muscle is irritated as it runs under the piriformis muscle in the buttocks. Finally, sacroiliac joint dysfunction can put pressure on the sciatic nerve, leading to sciatica.

Diagnosis

A physician will perform a physical exam on a patient complaining of sciatica in order to try to identify the part of the nerve that is irritated. This exam may include squatting, walking, standing on toes, and leg raising tests. Most commonly, lifting the leg to a 45° angle while holding it straight helps localize the pain. Other tests that may be performed include x ray to look for stress fractures in bones and magnetic resonance imaging (MRI) or computerized tomography (CT ) to look at softer tissues and ligaments. A nerve conduction velocity test and electromyography may also aid in diagnosis.

Treatment

In most cases, conservative treatments are effective for sciatica. A short period of rest, coupled with the application of cold packs and heat packs to the affected area, reduces inflammation of the nerve. Non-steroidal anti-inflammatory medicines can also be taken to decrease inflammation. Injection of corticosteriods may also be recommended to decrease swelling of the nerve. Physical therapy and short walks are also recommended.

If after three or more months, sciatica continues and become progressively worse, surgical techniques can be used to relieve the pressure on the sciatic nerve. Surgery is often very effective in relieving pain, although results can vary depending upon the cause of the sciatica. Overall, about 90% of patients undergoing surgery for sciatica pain receive some relief.

Recovery and rehabilitation

Usually, sciatica improves within a few weeks. In cases of severe injury to the nerve, such as laceration or other trauma, recovery may be not possible or may be limited. The extent of disability may vary from partial to complete loss of movement or sensation in the affected leg. Nerve pain may also persist.

Clinical trials

A recent drug trial found that the drug Remicade (infliximab), which is used to treat arthritis, is often effective for treating sciatica. The drug reduces the level of a chemical called tumor necrosis factor alpha, which plays an important role in the inflammatory response of the body. It is thought that this factor is also critical to sciatica.

The National Institutes of Health (NIH) are conducting three ongoing studies on the treatment of sciatica. One study investigates the effects of the antidepressants desipramine and benztropine on sciatica. A second looks at the effects of magnets on sciatica. A third investigates the role of two drugs, nortriptyline and MS Contin (a type of morphine), as treatment for sciatica. Contact information for these studies is the National Institute for Dental and Craniofacial Research (NIDCR), 9000 Rockville Pike, Bethesda, MD 20892; the toll-free number is (800) 411-1222.

Resources

BOOKS

Credit, Larry P., Sharon G. Hartunian, and Margaret J. Nowak. Relieving Sciatica. Vonore, TN: Avery Publishing Group, 2000.

Fishman, Loren, and Carol Ardman. Back Pain: How to Relieve Low Back Pain and Sciatica. New York: W.W. Norton and Company, 1997.

OTHER

Hochschuler, Stephen H. "What You Need to Know about Sciatica." SpineHealth.com. February 12, 2004 (April 4, 2004). <http://www.spine-health.com/topics/cd/d_sciatica/sc01.html>.

"Sciatica." American Association of Orthopaedic Surgeons. February 12, 2004 (April 4, 2004). http://orthoinfo.aaos.org/fact/thr_report.cfm?Thread_ID=167&topcategory=Spine.

"Sciatica." Harvard Medical Schools Consumer Health Information. February 12, 2004 (April 4, 2004). <http://www.intelihealth.com/IH/ihtIH/WSIHW000/9339/25686.html>.

ORGANIZATIONS

American Academy of Orthopaedic Surgeons. 6300 North River Road, Rosemont, IL 60018-4262. (847) 823-7186 or (800) 346-AAOS; Fax: (847) 823-8125. <http://www.aaos.org>.

National Institute of Arthritis and Musculoskeletal and Skin Diseases. Office of Communications and Public Liaison, National Institute of Health, Bldg. 31, Room 4C02 31 Center Dr. MSC 2350. Bethesda, MD 20892-2350. (301) 496-8190; Fax: (301) 480-2814. <http://www.niams.nih.gov/>.

Juli M. Berwald, PhD